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Class 10 Class 12

The sign of work done by a force on a body is important to understand. State carefully if the following quantities are positive or negative:
b) Work done by gravitational force when a man in lifting a bucket out of a well by means of a rope tied to the bucket.

Negative

In the given case, the direction of force (vertically downward) and displacement (vertically upward) are opposite to each other. Hence, the sign of work done is negative.
272 Views

What are different units of energy?

The different units of energy are :

(i) Joule
(ii) Erg
(iii) eV
(iv) KWh
(v) Calorie.

804 Views

Is work a scalar or a vector quantity?

Work is dot product of two vectors. i.e. .

And dot product is a scalar quantity. Therefore, work is a scalar quantity.
1450 Views

Define watt.

Power is said to be one watt if one joule of work is done in one second.
860 Views

What is watt?

SI unit of power is Watt.
773 Views

Define the unit joule.

Work done is said to be one joule if one newton of  force displaces the body through a distance of one meter in the direction of applied  force .
799 Views